Activated poly(hydromethylsiloxane)s as novel adhesion promoters for metallic surfaces

A poly(hydromethylsiloxane) (PHMS) was bound to aluminum, copper and steel surfaces rh activation with cis-[PtCl2(PhCH = CH2)(2)] in solution at room temperature. The attached polymer promotes the adhesion to two-component si licone resins where the curing process is based on catalytic hydrosilylatio n of olefins. In lap-shear or peel tests, cohesive failure was always obser ved. An example shows that the adhesive joint withstood boiling water for 2 00 h without considerable loss of adhesive strength. It is suggested that a small fraction of the olefinic component of the resin, e.g., a poly(dimeth ylsiloxane) containing some olefinic groups, is also connected with the att ached PHMS via catalytic hydrosilylation, thus binding the silicone resin t o the surface via the PHMS layer.